Wednesday, July 16, 2008

Covalent Solar may hold the key to increasing efficiency and cost effectiveness of solar energy. They just won the $20,000 MIT Student Team Award at the MIT Clean Energy Entrepreneurship Prize as well as another $10,000 the following day in the MIT $100k Business Plan Competition. Their simple, yet powerful idea is derived from concentrating sunlight onto smaller surface area rather than collecting it over a broader surface such as current solar panels. Their “Organic Solar Concentrators” look exactly like a quarter inch thick neon green piece of glass. However, the technology captures the light from the surfaces, redirects, and concentrates the light on the outer brim. The benefit comes from being able to create smaller photoelectric converters to turn the concentrated light on the brim into energy instead of large surface areas of solar panels such as the ones you are probably familiar with.

By focusing on a smaller area and device, Covalent Solar will be able to improve power conversion efficiency by 30% over the industry average. This reduces the installed cost per watt by 20% in 2014, and reduces the amortized cost of electricity to $0.12/kWh, hastening the onset of unsubsidized solar electricity competitive with the grid. Since the Organic Solar Concentrators come in sheets of transparent material, they can easily be fitted over current solar panels to increase extraction and efficiency of those devices. This breaks down an barrier to entry while enabling those with older technology to easily upgrade and improve return on investment.

The main costs for the concentrators come from the glass itself, which is dirt cheap at $5 to $10 per square meter, and the more costly dyes, which are about $50 per kilogram and are applied by a thermal evaporation technique. The end product may cost $100 to $400 per square meter, not including the solar cells around the edge.

According to a news release from MIT , the solar concentrator collects light at the edges, and dye molecules coated on the glass absorb sunlight and re-emits it at different wavelengths. The light is trapped within the glass and transported to solar cells along the edge, creating electricity and allowing light into the room as well.

The mixture of dyes is applied to the surface of the glass and allows light to travel a much longer distance. Mapel said, that as a result, light transportation losses were significantly reduced, resulting in a “tenfold increase in the amount of power converted by the solar cells.”

Marc A Baldo, leader of the work, is quoted as saying; “the focused light increases the electrical power obtained from each solar cell by a factor of over 40″. The article went on to say that because of its simplicity and ease of manufacture, the system could be implemented within three years. It could even be added to existing solar-panel systems, increasing their efficiency by 50 percent for minimal additional cost.